title: Mast cells can regulate skeletal muscle cell proliferation by multiple mechanisms.
abstract: BACKGROUND
  Mast cells (MCs) can stimulate cell proliferation, but their specific contribution to skeletal muscle regeneration is not well defined.
  
  
  METHODS
  L6 myoblast proliferation was assessed in coculture with MCs or when grown with MC-conditioned media. To address the in vivo implication of MCs in regeneration, rats were treated with cromolyn, and myoblast proliferation, immune cell accumulation, and myogenic factors were assessed in bupivacaine-injured muscles.
  
  
  RESULTS
  In vitro, both procedures increased the L6 cell proliferation rate, and this was tryptase-dependent. In vivo, MC stabilization increased myoblast proliferation and accumulation of macrophages CD68 and CD163 after injury. This correlated with a sequential increase in MyoD and myogenin protein level expression.
  
  
  CONCLUSIONS
  MCs can directly stimulate muscle cell proliferation via tryptase. MCs can influence myoblast proliferation in vivo, but this effect seems to be predominantly related to their modulation of macrophage recruitment. The MC is a potential actor in the early stages of muscle healing.
authors.affiliation: CHUQ Research Center and Faculty of Medicine, Laval University, 2705 Boulevard Laurier, RC-9800, Québec, G1V 4G2, Canada.
authors.forename: Elise
authors.initials: E
authors.lastname: Duchesne
authors.forename: Patrice
authors.initials: P
authors.lastname: Bouchard
authors.forename: Marie-Pier
authors.initials: MP
authors.lastname: Roussel
authors.forename: Claude H
authors.initials: CH
authors.lastname: Côté
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D049109:Cell Proliferation; D002478:Cells, Cultured; D018920:Coculture Techniques; D051546:Cyclooxygenase 2 / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D005786:Gene Expression Regulation; D007962:Leukocytes / Q000502:physiology; D008264:Macrophages / Q000378:metabolism; D008407:Mast Cells / Q000502:physiology*; D008565:Membrane Proteins / Q000378:metabolism; D032342:Muscle Cells / Q000502:physiology*; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000166:cytology*; D009135:Muscular Diseases / Q000378:metabolism / Q000473:pathology*; D009504:Neutrophils / Q000378:metabolism; D009842:Oligopeptides / Q000378:metabolism; D051763:PAX7 Transcription Factor / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D053802:Tryptases / Q000378:metabolism; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D051546:Cyclooxygenase 2; D008565:Membrane Proteins; D009124:Muscle Proteins; D009842:Oligopeptides; D051763:PAX7 Transcription Factor; D053802:Tryptases; C067980:CD68 antigen, human; D000097382:CD68 Molecule; C112356:seryl-leucyl-isoleucyl-glycyl--arginyl-leucinamide
keywords: leukocyte; macrophage; myoblast; myogenesis; tryptase